Boring implement



May 19, 1953 A, F. FRoussARD BORING IMPLEMENT Filed Sept. 26I 1949 Patented May 19, 1953 BORING IMPLEMENT'j Albert Froussard, St. Louis', Mo.

Application September 26, 41949, lSerial,N,0...117`,864.

4 Claims. 1-

This invention relates to -Y boring implements and rmoge particularly to such implemente for boring relatively long worle pieces.

The V'principal"object of the linvention is the provisionloti'a boring in iplemceht -for -boring fout relatively -longwork pieces,\of the type wherein a lcutter head is moved axially along a boring bar. so constructedvas to operatewithout -objectionable vibration while being of practicable size. The principal feature ofthe invention is the pro-- visiorronthe boring bar of va stiiien-ing beamr fixed to the bar extending parallelto and. spaced from the bar with thedcutte'r head in-slidingengage ment :with the -stiiiening beam throughout its range of movement on the -bary'the arrangement being such that stresses to which the fbar is subjeetedmby the .cutting actiom which stresses -are highest-When the cutterihead is -at the center of its range -of fmovernentf are ihr-part taken up `by the.. stiiiening 'beam 1- thereby resisting vibration. A

The boring implement ofllthisfinvention is particularly v adaptedior luse. on existinglathes `and is `particularly -suitable r for vtaper Ybring.- Other features will be in part apparent anden part pointed out. hereinafter.I

Theiinventienlaccordingly comprises the elements'and combinations of elements, features -o construction. and arrangements `of iparts which will he` exempliedin. the structures-hereinafter described, andf-.thef scopeof fthe application of which will :be indicated` in the-following claims.

Inthe.accompanying.drawing-in which one of various..possible'embodiments of` theinvention is illustrated, i

Fig. 1 is a longitudinal cross-section il1ustrating-a .boring `implement of -this 4invention onl a lathe,L Awith .parts Abroken `away Fig-2 isa plan -view oithelett end of Fig. 4-1;

Fig. 3 is a section on line- 3-3 offlpig'.` 1;

Figifiisgasectien on--lineA-Jl of Fig. 1; and

FigQ is a section on line 5 5 of Fig. l.

Similar reference characters; indicate. corresponding partsA throughout the several views of the drawing.

Referring to the drawing,a boring implement ringi'on a base |5,"the latter being nxed to the bed i ci the lathe. Thev `Work piece entends through the rings and is clamped -in `centered position by screws l1 threaded throughthe rings.

The boring implementd extends through' the work-piece. It comprises a rotatable borlngvbar l9;-herein illustrated as beingza solid bar of fcir.- cular,cross-section'having an axial lorjlongitudinal grooveextendingfrom one end Vto the other. One end ofthe bar isdetach'ably'coupled to ataper setting :device 21. vattached-to the face plate I! yof, theiathe The other end "of the bar is journalled for rotationand supported for rock# ing'rnovement in `a Vuniversal bearing yZiwliieh'is clamped-inthe steadyfrest `25 Aof the lathe.

The taper setting device 2t comprises, an adaptor plate 2 which-is bolted to the face plate il` othe` lathe. The adaptor plate, is,- provided withparallel guide .Ways 29 spaced equaldistances `onopposite sides 'of a line perpendicular tothe axis` ofthe `face plate `of `the lathe. A slide 3i is slidablygdovetailed `on the ways 2S for radial `adjustment with4 respect ito j the axis of j the `face plate fi I and the workpiece 3f, A nut 33 `projets froxngthey slide between'the Ways. An adjusting screw' .'iii 4is threaded through thenut. The screw 3islfjournalled in a plateixed at one end of the ways 129." On' the Vouter endof the. screw 35 and bearing vagtuinst the, plate 3'l"is'.an,adjusting Iknob 39 on'whichis scribed afdiallgjcalibrated in -units ,of rdistance, l:for example` .0 01 fnClLlJer graduation, readable in conjunction with an irl-.- dex mark'43 scribed `on the plate 37.V The Screw 35 is held against axial movement by a collarA d5 bearing against,` the side of theplate 31 aopposite the knob.- The arrangementgis such that 'by turning (the knob inY one direction or the other, the slide g3!" maybeadjusted radially toward por away from the ,axis-,of bthe, lathe ,faceplate ,to vary the eccentricity.of.the end of the borngjbar 'with respect to the Aaxisgoj the faceplate.;

The slide' V3l is `formedr with aclevis.,4l1, The boring cbar, 12 l: is' formedkwith a atend portion 'it' in ariane. at right angles. to thediametrical plane oi ,the groove A211." This dat ,end portion of, the bar ts inthe ,clevisend is. detachably vand pivotaliy cfJuQlSdtDeIetO, by meansof abou'. and nut corinectiomilL The boltrmay, be. tightened to lock the end of the boring bar. tothe,slide.. 3.l ,At .isehowma set screw threededthrouehfone side of the slide for locking the slide in adjusted position.

A cutter head 51 is axially slidable on the boring bar I9. The cutter head is made in the form of a collar encircling and having a sliding fit on the bar. In the cutter head are recesses 59 receiving cutting tools 6I projecting substantially radially from the head and held in the recesses by set screws 63. As shown, there are two such recesses and cutting tools. Both recesses (and tools) are aligned in the same diametrical plane. On the side of the cutter head diametrically opposite the tools, the cutter head is formed with an axial groove 65 of rectangular cross-section in its outer surface. This groove is centered with respect to the diametrical plane of the tools. A nut 61 is attached to the inside of the cutter head with its axis extending axially in respect to the cutter head and, as shown, located in the diametrical plane at right angles t the diametrical plane of the tools 6I and the groove 65. boring bar I9 with the nut 61 extending into the boring bar groove 2U, the latter being of crosssection corresponding to the shape of the nut so Vthat the nut slidably engages the surface of the groove. This keys the cutter head to the bar for rotation therewith, while permitting axial movement of the cutter head along the bar.

A planetating cutter head feed screw 69 extends axially of the boring bar in the groove from one end of the bar to the other and extends through the nut in threaded engagement therewith. Adjacent the flat end 49 of the boring bar, the feed screw is journalled in a bearing 1I xed to the bar. On the other end of the boring bar is a gear box 13. The feed screw extends into the gear box, being journalled in the wall of the box, and has a squared end 15 for application of a wrench manually to turn the screw. The gear box houses a gear train for turning the feed screw in response to rotation of the boring bar. In a simple version, as illustrated, this gear train includes a gear 11 xed on the feed screw and a pinion 19 in mesh with the gear. The pinion is provided with a squared hub 8| on which may be applied a socketed head 83 at the end of a rod 85, the latter being adapted for engagement with a fixed stop (not shown) to keep vthe pinion from turning about its axis as the boring bar rotates. It will be understood that gear trains of diierent ratios may be used, also lthat a reversing gear train may be used.

At 81 is shown a stiffening beam fixed at its .ends to the boring bar I9 to turn therewith extending parallel to and closely adjacent the bar substantially throughout the length of the bar. The beam is spaced from the bar a distance such that it extends through the groove 55 in the cutter head with `the cutter head in sliding erigagement with the beam. As shown, the beam consists of a bar of rectangular cross-section having a width corresponding to the width of the groove 65. The ends of the beam may be tapered on the outside as indicated at 89, for reduction in dimensions, and so that the beam approximates the form of a beam of constant strength. The inner side of the beam opposed to the boring bar is straight throughout its length for sliding engagement of the cutter head with the beam through the range of travel of the cutter head. As shown, vthe beam is xed at its ends in openings 9I in collars 93, the latter being fixed on the beam by set screws 95. Set screws 91 hold the ends of the beam in the collars.

In use, the slide 3I is adjusted to the setting The cutter head is mounted on the required for the taper to be bored. The lathe is driven to rotate the boring bar I9 and the cutter head 51 thereon. The stiffening beam 81 rotates with the bar. As the boring bar rotates, the cutter head 51 is moved axially along the bar by the feed screw E9. As the cutter head moves along the bar, it slides on the stiffening beam. Stresses arising from the cutting action of the cutting tools 6I are transmitted through the cutter head to the stiifening beam, the latter being located diametrically opposite the cutting tools to back up the cutter head and thus to resist bending and consequently to resist vibration. This is particularly important when the cutter head is being moved through the center of its range of movement at which time stresses tending to cause vibration are a maximum.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a. limiting sense.

I claim:

1. A boring implement comprising a rotatable boring bar having a longitudinal groove, a planetating feed screw carried by the bar in the groove, a cutter head axially slidable on the lbar, said cutter head .bein-g in the form of a collar encircling and having a sliding t on the bar and carrying a nut extending into the groove threaded on the screw and keying the cutter head to the bar for rotation therewith and axial movement therealong, a cutting tool projecting substantially radially from the head, and a stiiening beam consisting of a bar rigidly xed at its ends to the boring bar to turn therewith extending parallel to and closely adjacent the boring bar diametrically opposite the cutting tool, the cutter head being in sliding engagement with the stiifening beam.

2. A boring implement as set forth in claim 1 wherein the cutter head is in sliding engagement with the beam in an axial groove in the head.

3. A boring implement as set forth in claim l wherein the stiiening beam is rigidly xed at its ends to collars xed on the boring bar.

4. A .boring implement as set forth in claim l wherein the stiffening beam is of rectangular cross section with one of its sides opposed to the boring bar and straight throughout its length, the ends of the stiiIening beam being tapered on the opposite side, the cutter head having an axial rectangular groove receiving the beam, and the ends of the beam being rigidly vfixed in openings in collars xed on the boring bar.

64,553 Sweden Feb. "i, 1928 

